Welcome to FDMB!
Like Katrina, I whole heartedly disagree with your vet about home testing. If you look at the spreadsheets attached to our signatures, you see that we adjust doses routinely based on our home testing data. When I moved across states and found a new vet, she took one look at Gabby's spreadsheet and her only comment was, "You know what you're doing. Let me know if I can help."
Aside from dosing issues, there's an ever greater reason to home test. Without knowing what your cat's blood glucose level is, you have no clue if it's safe to give a shot. Your instincts were completely on target about not giving a shot last night -- you didn't want to inadvertently double dose. Without testing before giving insulin, you have not way to know if your cat's blood glucose is 400 or 40. You also have no way to know how low the dose is taking your kitty's numbers and if a dose reduction is needed.
If you're taking your cat to the vet for a curve, chances are your cat's blood glucose numbers are artificially inflated due to stress. Most of our cats are stressed out by a car ride and by being at the vet's office. As a result, the vet may recommend a dose increase. If you're testing at home, it's likely that you'd see lower numbers.
Not to twist your arm too much, we are huge advocates of home testing because it's the best way to keep your cat safe. Vets seem to have mistaken notions about how home testing affects your relationship with your cat. (They'll tell you your cat will end up hating you.) It's truly not the case.
